A new fast multi-beam-based method for adaptive beamforming in ultrasound imaging

The method of multi-beam beamforming is a low-computational adaptive beamforming method in which, instead of calculating the covariance matrix and inverting it for each point of the image, only one matrix is calculated for all points on the same radial distance. Then, to reduce the complexity of the inverse matrix calculation, the problem is solved in the beamspace domain. We introduce a new two-stage method to reduce the complexity of the minimum variance (MV) beamforming method, which outperforms the beamspace method in computational burden aspect in multi-beam method. In the first step, instead of using the signals of all array elements in calculating the covariance matrix, the signals of a decimated one are chosen such that the resulting covariance matrix contains all the correlation information of the signals. In the second stage, the weights of all elements of the array are determined by a proper interpolation method from the weights of the decimated array. According to the simulation results of point targets and cyst phantom, the new method has a performance similar to that of the beamspace multi-beam method in terms of resolution, contrast, and robustness against the errors with at least 3 times lower computational burden.